K + H2O
CHot)
K+ H2O (cold ) =
K+ H₂O (steam) =
Answers
Answer:
HOT WATER
Potassium metal reacts very rapidly with water to form a colourless solution of potassium hydroxide (KOH) and hydrogen gas (H2). The reaction is exothermic. Early in the reaction, the potassium metal becomes so hot that it catches fire and burns with a characteristic pale lilac colour.
COLD WATER
Potassium metal reacts very rapidly with water to form a colourless solution of potassium hydroxide (KOH) and hydrogen gas (H2). The resulting solution is basic because of the dissolved hydroxide. The reaction is exothermic.
STEAM
It reacts with steam when being heated and gives hydrogen gas and metal oxide. Potassium melts to a silvery ball, moves quickly on the water surface with a hissing sound, and burns with a lilac flame. The resulting alkaline solution will turn red litmus blue because of the potassium hydroxide formed.
Explanation:
Answer:
Explanation:
On average seawater contains 1-10 ppt of tin, and river water contains 6-40 ppt. The Lacuta seaweed generally contains 12 ppb of tin, and mussles contain up to 160 ppb (dry mass). Dissolved in water tin generally occurs as SnO(OH)3-, and in both seawater and freshwater mono-, di- and trimethyltin compounds can be found. This are partially decomposed to volatile compounds.
In what way and in what form does tin react with water?
Under normal circumstances tin is stable in water. When it comes in contact with hot water vapour a reaction results, forming tinoxide and hydrogen:
Sn + 2 H2O -> SnO2 + 2 H2
Some tin compounds hydrolyse in water. Examples include tin (IV) chloride, which forms tinoxide when heated.
Solubility of tin and tin compounds
Elementary tin does not dissolve in water under normal conditions (T = 20oC and pressure = 1 bar). Most tin compounds do not dissolve in water either, examples include tin (IV) oxide, tin (II) hydroxide, tin (IV) sulphide and tributyltin (TBT). Other tin compounds such as tin (II) chloride are water soluble. Organotin compounds are relatively badly water soluble, but may adsorb to sediments.
Why is tin present in water?
A number of tin minerals occur naturally, of which only cassiterite plays a role in commercial processes. Its main constituent tin (IV) oxide is water soluble and thereby weathering is prevented. The naturally occurring amount of tin in soils and water is relatively small. The release of tin from anthropogenic processes exceeds tin release from geological processes 110 times.
Tin is applied as a protective layer on iron cans to prevent corrosion. This property is mainly applied in conserve can production, and relatively large amounts of tin may enter the food chain through weathering from unvarnished cans. Conserve cans are partially recycled. Tin is present in various alloys, such as soldering tin, bronze and amalgam for dentistry. However, most tin is applied in cans.
Tin compounds such as TBT are applied as polymer additives in antifouling paint as a ship hull preservative. In a thin layer these may serve as a protective coating on glass and ceramics. Tin (II) chloride is a reductive agent, and tin (IV) sulphide serves as tin bronze for paints. Tin (II) fluoride is added to toothpaste.
Organotin compounds are applied as fungicides, insecticides, acaricides and bactericides. Additionally, these are applied as PVC and PCB heat stabilizers.
Superconductor magnets, cylinder blocks in engines and drum brakes contain this metal. TBT oxide is applied for wall paper soaking, as a wood preservative, and for sludge removal from industrial wastewater. It is a constituent of fire extinguishers, and of electro-industrial wastewater. When security measures are inadequate, tin and tin compounds may end up in the environment.
Radioactive tin isotopes are applied in nuclear physics.